Detectors of mm-wavelength radiation and detectors of IR radiation are both known in the art. One material that is well-suited to fabricating mm-wavelength detectors and associated high-speed amplifier circuitry is a Group III--V material, such as GaAs.
The following articles describe various millimeter and submillimeter receivers: "SIS Receivers for Submillimeter Wave Astronomy", First International Symposium on Space Terahertz Technology, T. G. Philips et al., page 343; "A Low Noise Receiver for Millimeter and Submillimeter Wavelengths", M. J. Wengler et al , International Journal of Infrared and Millimeter Waves, Vol. 6, No. 8, 1985, pages 697-701; and "A Low Noise Receiver for Submillimeter Astronomy", M. J. Wengler et al , SPIE Vol 598, Instrumentation for Submillimeter Spectroscopy, 1985, pages 27-29. The first article listed above shows the use of a spiral antenna and a hyperhemispheric lens, while the second and third articles show a bowtie antenna configuration used in conjunction with a hyperhemispheric lens.
IR detectors may be fabricated from material selected from Group II-VI of the periodic table=, such as Hg.sub.(1-x) Cd.sub.x Te, wherein x varies within a range of approximately 0.2 for long wavelength IR (LWIR) to a value of approximately 0.4 for short wavelength IR (SWR).
For some applications it may be desirable to provide both mm-wave and IR detectors for simultaneously viewing a scene that include a source of mm-waves and also a source of IR radiation. However, the fabrication of a detector or detectors, from one type of material, that is responsive to both sources of radiation is difficult or impossible to achieve.
It is thus an object of the invention to provide an integrated detector structure that is simultaneously responsive to sub-millimeter or millimeter wavelength radiation and also to IR radiation.